The present invention relates to die casting vacuum valves and, more particularly, to a vacuum valve system coupled with a die cast pair to evacuate fluid, such as air, from the die cavity prior to injection of a molten material into the cavity.
In vacuum die casting, it is desirous to remove air and gasses from the casting cavity prior to injection of a molten metal shot. Evacuation of the cavity is generally accomplished by a venting device coupled with the cavity and mold dies. Optimum evacuation results in optimum flow of the molten material into the cavity which, in turn, eliminates poor surface finish, porosity and provides a desired casting.
Several types of systems and valves exist which attempt to evacuate the die cavity. The systems and valves are illustrated by the following U.S. patents: F. Hodler U.S. Pat. No. 2,785,448, Mar. 19, 1957; F. Hodler U.S. Pat. No. 2,867,869, Jan. 13, 1959; D. M. Morgenstern U.S. Pat. No. 2,904,861, Sept. 22, 1959; W. Venus U.S. Pat. No. 3,070,857, Jan. 1, 1963; F. Hodler U.S. Pat. No. 3,433,291, Mar. 18, 1969; Hodler U.S. Pat. No. 3,885,618, May 27, 1975; Hodler U.S. Pat. No. 4,027,726, June 7, 1977; Ernst et al U.S. Pat. No. 4,729,422, Mar. 8, 1988; Ruhlandt et al U.S. Pat. No. 4,779,666, Oct. 25, 1988; Uchida et al U.S. Pat. No. 4,782,886,Nov. 8, 1988; Voss et al U.S. Pat. No. 4,809,767, Mar. 7, 1989; Voss et al U.S. Pat. No. 4,825,933, May 2, 1989; Klenk U.S. Pat. No. 4,832,109, May 23, 1989. While the above patents appear to perform satisfactorily for their intended purpose, designers are always striving to improve the art.
Accordingly, the present invention provides the art with a new and improved vacuum valve adapted to be coupled with a casting die pair or integrated with the die blocks in a vacuum casting apparatus. The present invention provides the art with a vacuum valve which includes a cushioning mechanism which prevents excessive wear on the interior of the valve housing. The present invention provides a vacuum valve which is coupled with a controller to close the vacuum valve as the shot is injected into the die cavity. Also the invention provides the art with a vacuum valve that is relatively simple and economical in manufacture and repair.
From the below detailed description taken in conjunction with the accompanying drawings and subjoined claims, other objects and advantages of the present invention will become apparent to those skilled in the art.